X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Ftimeval.c;h=4ed3ebff5ddafaae9cd5c35a9b04ff45cf876804;hb=cc36576070df622d0fc7a6e26ce01027e12b5b59;hp=27a5fc761d4868e0449791f42a195c106df50b36;hpb=6f2302b06c5ca19ed143b01a01031de56b229306;p=sliver-openvswitch.git diff --git a/lib/timeval.c b/lib/timeval.c index 27a5fc761..4ed3ebff5 100644 --- a/lib/timeval.c +++ b/lib/timeval.c @@ -18,6 +18,7 @@ #include "timeval.h" #include #include +#include #include #include #include @@ -38,37 +39,37 @@ VLOG_DEFINE_THIS_MODULE(timeval); -/* The clock to use for measuring time intervals. This is CLOCK_MONOTONIC by - * preference, but on systems that don't have a monotonic clock we fall back - * to CLOCK_REALTIME. */ -static clockid_t monotonic_clock; +struct clock { + clockid_t id; /* CLOCK_MONOTONIC or CLOCK_REALTIME. */ + pthread_rwlock_t rwlock; /* Mutual exclusion for 'cache'. */ -/* Has a timer tick occurred? Only relevant if CACHE_TIME is true. - * - * We initialize these to true to force time_init() to get called on the first - * call to time_msec() or another function that queries the current time. */ -static volatile sig_atomic_t wall_tick = true; -static volatile sig_atomic_t monotonic_tick = true; + /* Features for use by unit tests. Protected by 'rwlock'. */ + struct timespec warp; /* Offset added for unit tests. */ + bool stopped; /* Disables real-time updates if true. */ + + /* Relevant only if CACHE_TIME is true. */ + volatile sig_atomic_t tick; /* Has the timer ticked? Set by signal. */ + struct timespec cache; /* Last time read from kernel. */ +}; -/* The current time, as of the last refresh. */ -static struct timespec wall_time; -static struct timespec monotonic_time; +/* Our clocks. */ +static struct clock monotonic_clock; /* CLOCK_MONOTONIC, if available. */ +static struct clock wall_clock; /* CLOCK_REALTIME. */ /* The monotonic time at which the time module was initialized. */ static long long int boot_time; -/* features for use by unit tests. */ -static struct timespec warp_offset; /* Offset added to monotonic_time. */ -static bool time_stopped; /* Disables real-time updates, if true. */ - -/* Time in milliseconds at which to die with SIGALRM (if not LLONG_MAX). */ +/* Monotonic time in milliseconds at which to die with SIGALRM (if not + * LLONG_MAX). */ static long long int deadline = LLONG_MAX; +/* Monotonic time, in milliseconds, at which the last call to time_poll() woke + * up. */ +DEFINE_PER_THREAD_DATA(long long int, last_wakeup, 0); + static void set_up_timer(void); static void set_up_signal(int flags); static void sigalrm_handler(int); -static void refresh_wall_if_ticked(void); -static void refresh_monotonic_if_ticked(void); static void block_sigalrm(sigset_t *); static void unblock_sigalrm(const sigset_t *); static void log_poll_interval(long long int last_wakeup); @@ -77,30 +78,38 @@ static void refresh_rusage(void); static void timespec_add(struct timespec *sum, const struct timespec *a, const struct timespec *b); -/* Initializes the timetracking module, if not already initialized. */ static void -time_init(void) +init_clock(struct clock *c, clockid_t id) { - static bool inited; + memset(c, 0, sizeof *c); + c->id = id; + xpthread_rwlock_init(&c->rwlock, NULL); + xclock_gettime(c->id, &c->cache); +} - if (inited) { - return; - } - inited = true; +static void +do_init_time(void) +{ + struct timespec ts; coverage_init(); - if (!clock_gettime(CLOCK_MONOTONIC, &monotonic_time)) { - monotonic_clock = CLOCK_MONOTONIC; - } else { - monotonic_clock = CLOCK_REALTIME; - VLOG_DBG("monotonic timer not available"); - } + init_clock(&monotonic_clock, (!clock_gettime(CLOCK_MONOTONIC, &ts) + ? CLOCK_MONOTONIC + : CLOCK_REALTIME)); + init_clock(&wall_clock, CLOCK_REALTIME); + boot_time = timespec_to_msec(&monotonic_clock.cache); set_up_signal(SA_RESTART); set_up_timer(); +} - boot_time = time_msec(); +/* Initializes the timetracking module, if not already initialized. */ +static void +time_init(void) +{ + static pthread_once_t once = PTHREAD_ONCE_INIT; + pthread_once(&once, do_init_time); } static void @@ -125,7 +134,7 @@ set_up_timer(void) return; } - if (timer_create(monotonic_clock, NULL, &timer_id)) { + if (timer_create(monotonic_clock.id, NULL, &timer_id)) { VLOG_FATAL("timer_create failed (%s)", ovs_strerror(errno)); } @@ -146,95 +155,107 @@ set_up_timer(void) void time_postfork(void) { + assert_single_threaded(); time_init(); set_up_timer(); } -static void -refresh_wall(void) +/* Forces a refresh of the current time from the kernel. It is not usually + * necessary to call this function, since the time will be refreshed + * automatically at least every TIME_UPDATE_INTERVAL milliseconds. If + * CACHE_TIME is false, we will always refresh the current time so this + * function has no effect. */ +void +time_refresh(void) { - time_init(); - xclock_gettime(CLOCK_REALTIME, &wall_time); - wall_tick = false; + monotonic_clock.tick = wall_clock.tick = true; } static void -refresh_monotonic(void) +time_timespec__(struct clock *c, struct timespec *ts) { time_init(); - - if (!time_stopped) { - if (monotonic_clock == CLOCK_MONOTONIC) { - xclock_gettime(monotonic_clock, &monotonic_time); - } else { - refresh_wall_if_ticked(); - monotonic_time = wall_time; + for (;;) { + /* Use the cached time by preference, but fall through if there's been + * a clock tick. */ + xpthread_rwlock_rdlock(&c->rwlock); + if (c->stopped || !c->tick) { + timespec_add(ts, &c->cache, &c->warp); + xpthread_rwlock_unlock(&c->rwlock); + return; } - timespec_add(&monotonic_time, &monotonic_time, &warp_offset); + xpthread_rwlock_unlock(&c->rwlock); - monotonic_tick = false; + /* Refresh the cache. */ + xpthread_rwlock_wrlock(&c->rwlock); + if (c->tick) { + c->tick = false; + xclock_gettime(c->id, &c->cache); + } + xpthread_rwlock_unlock(&c->rwlock); } } -/* Forces a refresh of the current time from the kernel. It is not usually - * necessary to call this function, since the time will be refreshed - * automatically at least every TIME_UPDATE_INTERVAL milliseconds. If - * CACHE_TIME is false, we will always refresh the current time so this - * function has no effect. */ +/* Stores a monotonic timer, accurate within TIME_UPDATE_INTERVAL ms, into + * '*ts'. */ void -time_refresh(void) +time_timespec(struct timespec *ts) +{ + time_timespec__(&monotonic_clock, ts); +} + +/* Stores the current time, accurate within TIME_UPDATE_INTERVAL ms, into + * '*ts'. */ +void +time_wall_timespec(struct timespec *ts) +{ + time_timespec__(&wall_clock, ts); +} + +static time_t +time_sec__(struct clock *c) { - wall_tick = monotonic_tick = true; + struct timespec ts; + + time_timespec__(c, &ts); + return ts.tv_sec; } /* Returns a monotonic timer, in seconds. */ time_t time_now(void) { - refresh_monotonic_if_ticked(); - return monotonic_time.tv_sec; + return time_sec__(&monotonic_clock); } /* Returns the current time, in seconds. */ time_t time_wall(void) { - refresh_wall_if_ticked(); - return wall_time.tv_sec; + return time_sec__(&wall_clock); +} + +static long long int +time_msec__(struct clock *c) +{ + struct timespec ts; + + time_timespec__(c, &ts); + return timespec_to_msec(&ts); } /* Returns a monotonic timer, in ms (within TIME_UPDATE_INTERVAL ms). */ long long int time_msec(void) { - refresh_monotonic_if_ticked(); - return timespec_to_msec(&monotonic_time); + return time_msec__(&monotonic_clock); } /* Returns the current time, in ms (within TIME_UPDATE_INTERVAL ms). */ long long int time_wall_msec(void) { - refresh_wall_if_ticked(); - return timespec_to_msec(&wall_time); -} - -/* Stores a monotonic timer, accurate within TIME_UPDATE_INTERVAL ms, into - * '*ts'. */ -void -time_timespec(struct timespec *ts) -{ - refresh_monotonic_if_ticked(); - *ts = monotonic_time; -} - -/* Stores the current time, accurate within TIME_UPDATE_INTERVAL ms, into - * '*ts'. */ -void -time_wall_timespec(struct timespec *ts) -{ - refresh_wall_if_ticked(); - *ts = wall_time; + return time_msec__(&wall_clock); } /* Configures the program to die with SIGALRM 'secs' seconds from now, if @@ -272,15 +293,16 @@ int time_poll(struct pollfd *pollfds, int n_pollfds, long long int timeout_when, int *elapsed) { - static long long int last_wakeup = 0; + long long int *last_wakeup = last_wakeup_get(); long long int start; sigset_t oldsigs; bool blocked; int retval; + time_init(); time_refresh(); - if (last_wakeup) { - log_poll_interval(last_wakeup); + if (*last_wakeup) { + log_poll_interval(*last_wakeup); } coverage_clear(); start = time_msec(); @@ -326,33 +348,16 @@ time_poll(struct pollfd *pollfds, int n_pollfds, long long int timeout_when, if (blocked) { unblock_sigalrm(&oldsigs); } - last_wakeup = time_msec(); + *last_wakeup = time_msec(); refresh_rusage(); - *elapsed = last_wakeup - start; + *elapsed = *last_wakeup - start; return retval; } static void sigalrm_handler(int sig_nr OVS_UNUSED) { - wall_tick = true; - monotonic_tick = true; -} - -static void -refresh_wall_if_ticked(void) -{ - if (!CACHE_TIME || wall_tick) { - refresh_wall(); - } -} - -static void -refresh_monotonic_if_ticked(void) -{ - if (!CACHE_TIME || monotonic_tick) { - refresh_monotonic(); - } + monotonic_clock.tick = wall_clock.tick = true; } static void @@ -437,7 +442,9 @@ log_poll_interval(long long int last_wakeup) { long long int interval = time_msec() - last_wakeup; - if (interval >= 1000 && !warp_offset.tv_sec && !warp_offset.tv_nsec) { + if (interval >= 1000 + && !monotonic_clock.warp.tv_sec + && !monotonic_clock.warp.tv_nsec) { const struct rusage *last_rusage = get_recent_rusage(); struct rusage rusage; @@ -478,37 +485,66 @@ struct cpu_usage { unsigned long long int cpu; /* Total user+system CPU usage when sampled. */ }; -static struct rusage recent_rusage; -static struct cpu_usage older = { LLONG_MIN, 0 }; -static struct cpu_usage newer = { LLONG_MIN, 0 }; -static int cpu_usage = -1; +struct cpu_tracker { + struct cpu_usage older; + struct cpu_usage newer; + int cpu_usage; + + struct rusage recent_rusage; +}; +DEFINE_PER_THREAD_MALLOCED_DATA(struct cpu_tracker *, cpu_tracker_var); + +static struct cpu_tracker * +get_cpu_tracker(void) +{ + struct cpu_tracker *t = cpu_tracker_var_get(); + if (!t) { + t = xzalloc(sizeof *t); + t->older.when = LLONG_MIN; + t->newer.when = LLONG_MIN; + cpu_tracker_var_set_unsafe(t); + } + return t; +} static struct rusage * get_recent_rusage(void) { - return &recent_rusage; + return &get_cpu_tracker()->recent_rusage; +} + +static int +getrusage_thread(struct rusage *rusage OVS_UNUSED) +{ +#ifdef RUSAGE_THREAD + return getrusage(RUSAGE_THREAD, rusage); +#else + errno = EINVAL; + return -1; +#endif } static void refresh_rusage(void) { - long long int now; + struct cpu_tracker *t = get_cpu_tracker(); + struct rusage *recent_rusage = &t->recent_rusage; - now = time_msec(); - getrusage(RUSAGE_SELF, &recent_rusage); - - if (now >= newer.when + 3 * 1000) { - older = newer; - newer.when = now; - newer.cpu = (timeval_to_msec(&recent_rusage.ru_utime) + - timeval_to_msec(&recent_rusage.ru_stime)); - - if (older.when != LLONG_MIN && newer.cpu > older.cpu) { - unsigned int dividend = newer.cpu - older.cpu; - unsigned int divisor = (newer.when - older.when) / 100; - cpu_usage = divisor > 0 ? dividend / divisor : -1; - } else { - cpu_usage = -1; + if (!getrusage_thread(recent_rusage)) { + long long int now = time_msec(); + if (now >= t->newer.when + 3 * 1000) { + t->older = t->newer; + t->newer.when = now; + t->newer.cpu = (timeval_to_msec(&recent_rusage->ru_utime) + + timeval_to_msec(&recent_rusage->ru_stime)); + + if (t->older.when != LLONG_MIN && t->newer.cpu > t->older.cpu) { + unsigned int dividend = t->newer.cpu - t->older.cpu; + unsigned int divisor = (t->newer.when - t->older.when) / 100; + t->cpu_usage = divisor > 0 ? dividend / divisor : -1; + } else { + t->cpu_usage = -1; + } } } } @@ -520,7 +556,7 @@ refresh_rusage(void) int get_cpu_usage(void) { - return cpu_usage; + return get_cpu_tracker()->cpu_usage; } /* Unixctl interface. */ @@ -532,7 +568,10 @@ timeval_stop_cb(struct unixctl_conn *conn, int argc OVS_UNUSED, const char *argv[] OVS_UNUSED, void *aux OVS_UNUSED) { - time_stopped = true; + xpthread_rwlock_wrlock(&monotonic_clock.rwlock); + monotonic_clock.stopped = true; + xpthread_rwlock_unlock(&monotonic_clock.rwlock); + unixctl_command_reply(conn, NULL); } @@ -556,8 +595,11 @@ timeval_warp_cb(struct unixctl_conn *conn, ts.tv_sec = msecs / 1000; ts.tv_nsec = (msecs % 1000) * 1000 * 1000; - timespec_add(&warp_offset, &warp_offset, &ts); - timespec_add(&monotonic_time, &monotonic_time, &ts); + + xpthread_rwlock_wrlock(&monotonic_clock.rwlock); + timespec_add(&monotonic_clock.warp, &monotonic_clock.warp, &ts); + xpthread_rwlock_unlock(&monotonic_clock.rwlock); + unixctl_command_reply(conn, "warped"); }